In fire detection apparatus the accumulation-type control panel is designed for the purpose of preventing a false fire alarm from being produced by transient fire phenomena, and gives a fire indication or alarm only if it has decided that a fire detector has been continuously detecting a fire phenomenon exceeding a predetermined fire detection level for a predetermined length of time.
In the case of the accumulation-type control panel which continues the accumulating operation without resetting the fire detector, however, it is not practicable to use a conventional fire detector having a latching function for the following reason. The conventional latching fire detector, once having detected a fire phenomenon (e.g., heat, smoke, light from flame, gas) exceeding the predetermined fire level, keeps its fire signal transmission circuit (or the circuit which controls the signal transmission circuit) activated and continues transmitting the fire signal even if the fire phenomenon disappeared immediately after the initial detection. Therefore, the accumulation-type control panel, if connected with such a latching fire detector, has the drawback that it operates on the transient fire phenomenon as well and produces a false fire alarm.
Accordingly, it is preferable to connect a non-latching type fire detector to an accumulation-type control panel. The non-latching type fire detector outputs the fire signal only while the fire phenomenon is exceeding the predetermined fire level and stops outputting the fire signal as soon as the fire phenomenon falls below the fire level.
When the accumulation-type control panel is connected to a plurality of non-latching type fire detectors, each equipped with a response indicator lamp to indicate that the fire detection part is active, there is the new problem that one cannot know which fire detector initiated the fire signal to operate the accumulation-type control panel because the response indicator lamp is lit only while the fire detector is outputting the fire signal, and goes off as generation of the fire signal is stopped.